This invention relates to luminaires. More particularly, this invention relates to heat absorbing devices (i.e., heat sinks) that remove heat from luminaires.
Conventional luminaires with low wattage lamps and relatively large housings typically do not exceed operating temperature limits because of heat generated by their lamps. Space within the luminaire and around the lamp(s) is often more than adequate to allow generated heat to dissipate harmlessly into the surrounding air via convection. Convection causes hotter air to rise higher than cooler air. Thus, so long as sufficient space is available, cooler air tends to be circulated toward a heat generating device as hotter air is naturally circulated away.
However, many new luminaires are compact in size and have high wattage lamps. Accordingly, more heat is generated in less space, rendering convective air cooling alone inadequate, and thus resulting in higher operating temperatures. These higher temperatures may exceed the lamp manufacturers' specifications, causing lamps to prematurely fail. Excessive heat may also cause other luminaire components or electrical connections to fail. Accordingly, heat removal from such compact, high wattage luminaires is an important design consideration.
Passive heat sinks are known. Such devices are typically metal or other thermally conductive material attached to a component from which heat is transferred to the heat sink. The heat then radiates from the heat sink into the surrounding air. In many cases, passive heat sinks provide sufficient cooling to maintain components below their specified temperature limits. However, for heat sinks to be effective, particularly in high heat environments, they should have large amounts of surface area from which to radiate the heat. The more surface area, the more heat that can be transferred from the attached component to the surrounding air. Accordingly, some heat sinks have numerous fins, bends, or folds to increase surface area. This, however, causes many heat sinks to be large and bulky, rendering them impractical for use in compact luminaires.
In view of the forgoing, it would be desirable to be able to provide a heat sink for a luminaire that can remove sufficient lamp heat to prevent premature lamp failure.
It would also be desirable to be able to provide a heat sink for a luminaire that is compact, installs securely against a lamp socket, allows lamp wiring to exit the socket, and still provides access to the socket when needed.